Why a space-based missile interceptor system is not viable

A map that shows the relative missile defense interceptor coverage of a certain array of space-based platforms.

The United States has plans to develop two new missile defense programs in the space domain: a space-based sensor architecture and a space-based missile intercept layer. Both proposed systems rely on a network of satellites in low Earth orbit to offer full or partial coverage of the Earth’s surface, precisely tracking a missile during its flight in one case, or shooting it down entirely in the other. A space-based sensor system could expand current capabilities for monitoring missile launches and warrants further study. The deployment of a space-based missile intercept layer, however, would require launching hundreds or thousands of weapons into space – an expensive, inefficient, and provocative idea. The technical discussion surrounding space-based interceptors should be decoupled from that of space-based sensors – a much more plausible proposal. Despite decades of support from influential policymakers, the resources required to deploy space-based interceptors would be better spent on other layers of US missile defense.